Primer attachment for carburetors



March 4, 1969 c, A 3,430,933

PRIMER ATTACHMENT FOR CARBURETORS Filed D60. 14, 1967 Z7 Z6 F l 22 L 2/ V V /6 INVENTOR. MEL W4 6. TMGART mm Hi 9% ATTYS United States Patent Office 3,430,933 Patented Mar. 4, 1969 ABSTRACT OF THE DISCLOSURE A primer attachment for a carburetor is described for assisting in the starting of a relatively constant r.p.m. gasoline engine that does not have an accelerator fuel pump. The carburetor attachment includes a threaded tubular fitting that replaces the exterior plug used to provide access to the main fuel nozzle chamber. Tubing is connected to the fitting. A compressible bulb is connected to the tubing for forcing air through the tubing and into the main fuel nozzle chamber to push fuel into the carburetor throat prior to starting the engine. A check valve is mounted in the tubing for preventing fluid flow from the main nozzle chamber.

Background of the invention This invention relates to primers for internal combustion engines and more particularly to primer attachments for carburetors that do not have accelerator pumps for supplying fuel to the carburetor throat to assist in starting the engines.

Carburetors for some variable r.p.m. gasoline engines, such as those for automobiles, are provided with accelerator pumps in the carburetor fuel bowl for supplying fuel to the carburetor throat prior to starting the engine. However, many gasoline engines are designed to operate at relatively constant rpm. and do not require an accelerator pump for varying the flow of fuel to the carburetor throat. Such engines include those used in tractors, road graders and stationary power plants. To start the constant r.p.rn. gasoline engines, the operator generally either has to crank the engine to develop a suflicient vacuum in the intake manifold to draw air through the carburetor to suck fuel from the fuel jets into the manifold or to spray fuel into the top of the carburetor or into the manifold. The cranking method requires a great deal of physical effort and is frequently ineffective to start the engine on cold days or after the engine has been idle for a long period of time. The second method requires an outside source of fuel or starting fluid and is quite expensive and frequently cumbersome.

One of the principal objects of this invention is to provide a primer attachment for carburetors that is easy to operate and eflicient in operation to assure that fuel is available in the intake manifold prior to starting the engine.

An additional object of this invention is to provide a primer attachment for a carburetor that is inexpensive and may be easily installed by inexperienced personnel.

A further object of this invention is to provide a primer attachment for a carburetor that does not require an external fuel or starting fluid source.

These and other objects of this invention will become apparent upon reading the following description of a preferred embodiment of this invention.

in the accompanying drawing in which:

FIG. 1 is a schematic side elevation view of a carburetor that receives air from an air cleaner and injects fuel into the air stream as the air passes to the intake manifold of the engine. A primer attachment embodying the principles of this invention is shown attached to the carburetor; and

FIG. 2 is a vertical cross sectional view of the carburetor and the primer attachment emphasizing the details of the attachment with respect to the carburetor.

Detailed description of the preferred embodiment Referring now in detail to the drawings, a carburetor 10 is illustrated in FIG. 1 with an air filter unit 11 mounted on the air intake line of the carburetor. The outlet line of the carburetor is connected to the intake engine manifold 13. A carburetor attachment, generally designated by the numeral 14, is shown mounted to and connected with the carburetor.

As shown in the cross sectional view of FIG. 2, the carburetor has a housing 15. The housing 15 includes a fuel bowl 16 that serves as a small fuel reservoir. Fuel floats 17 are positioned in the bowl to regulate the flow of the fuel from a fuel pump to the carburetor. From the fuel bowl the fuel flows through a passage 18 to a main fuel nozzle chamber 20. A manual needle valve 21 extends into the passage 18 to adjust the flow of the fuel from the fuel bowl to the main fuel nozzle chamber. A main metering rod 22 is mounted in the chamber 20 for controlling the flow of fluid therethrough. The metering rod 22 has a threaded head 23 that permits the adjustment of the position of the metering rod 22.

Normally an external closure plug (not shown) is mounted in the end of the chamber 20 to permit access to the adjustment head 23 for adjusting the position of the main metering rod 22.

The carburetor attachment 14 includes a bracket 26 that is mounted to the carburetor housing 15 and extends horizontally outwardly therefrom. The bracket 26 has a hole 27 formed therein for receiving elements of the carburetor attachment to support the attachment adjacent the carburetor to provide easy access for the operator to prime the carburetor.

The carburetor attachment includes a threaded tubular fitting 28 that replaces the exterior plug in the main fuel nozzle chamber 20 to provide fluid communication between elements of the carburetor attachment and the main fuel nozzle chamber 20. The threaded fitting 28 has an appropriate seal to prevent leakage. A flexible tubing 30 made of rubber or plastic is connected to the threaded fitting 28, with one tubing end 31 deformed over the end of the threaded fitting 27 to provide a leakproof connection.

A check valve 32 is mounted in the flexible tubing 30 near the end 31 to permit the flow of air through the tubing into the main fuel nozzle chamber 20 but to prevent the fiow of air or fluid in the opposite direction from the main fuel nozzle chamber 20. The other end 33 of the flexible tubing 30 extends upwardly through the hole 27 in the bracket 26 to fit over one end of a tubing fitting 34.

A resilient compressible plastic or rubber bulb 36 is mounted on the other end of the tubing fitting 34 for forcing air through'the tubing and into the main fuel nozzle chamber 20 to push fuel into the throat of the carburetor. A check valve 37 is mounted in the wall of the bulb 36 to permit the bulb to refill with air after it has been compressed and released.

When the operator wishes to start the engine he merely compresses the bulb 36 to force air through the flexible tubing 30 and into the main fuel nozzle chamber 20 to force fuel through the nozzle jets and into the carburetor throat so that there is suflicient fuel with which to start combustion in the engine.

From the above description one may readily appreciate the simplicity of the carburetor attachment and the efficiency with which it performs the task of priming the carburetor to start the gasoline engine.

It is understood that the above described embodiment is simply illustrative of the principles of this invention and numerous other modifications may be made to the described embodiment without deviating from the principles of this invention.

What I claim as my invention is:

1. An attachment for a carburetor that has an exterior plug for the main fuel nozzle chamber but no accelerator pump for supplying fuel to the carburetor throat to assist in starting an internal combustion engine, said carburetor attachment comprising:

(a) a threaded tubular fitting for replacing the exterior plug to provide air communication with the main fuel nozzle chamber;

(b) a flexible tubing having one end connected to the threaded fitting;

(c) a valve device mounted in the flexible tubing for permitting fluid to flow through the tubing to the main fuel nozzle chamber and for preventing fluid flow through the tubing in the opposite direction from the fuel nozzle chamber; and

(d) an air pressure bulb connected to the other end of the flexible tubing for forcing the air through the tubing into the main fuel nozzle chamber to force fuel to flow to the carburetor throat to start the engine.

2. A carbureton attachment as defined in claim 1 further comprising: a bracket attached to the exterior of the carburetor for supporting the tubing and the bulb adjacent the carburetor.

3. A carburetor attachment as defined in claim 1 further comprising an air supply valve mounted in the wall of the bulb for permitting air to flow from the atmosphere into the bulb to inflate the bulb after it has been compressed and released.

4. A carburetor attachment as defined in claim 3 wherein the valve device mounted in the flexible tubing is a one-way check valve.

5. A carburetor attachment as defined in claim 4 further comprising a fitting interconnecting the bulb and the tubing to prevent air leakage therebetween.

References Cited UNITED STATES PATENTS 3,275,305 9/1966 Nutten 26134 3,281,129 10/1966 Payne 261-34 3,307,836 3/1967 Amdt et a1 261-34 FOREIGN PATENTS 598,578 9/1925 France.

TIM R. MILES, Primary Examiner.

US. Cl. X.R. 

